Insulated roller-bearing.



'0. E. WIESELGREEN.

INSULATED ROLLER BEARING APPLICATION FILED JULY 18, I914.

Patented Sept. 7, 1915.

UNITED STATES PATENT oEEIcE.

CARL Ell/[IL WIESELGREEN, OF GOTTENBOBG, SWEDEN, ASSIGNOR T AKTIEBOLAGETSVENSKA KULLAGERFABRIKEN, OF GOTTENBORG, SWEDEN, A CORPORATION OFSWEDEN.

Specification of Letters Patent.

Patented Sept. 7, 1915.

Application filed July 18, 1914. Serial No. 851,698.

To all whom it may concern Be it known that I, CARL EMIL WIEsEL- GREEN,a citizen of the Kingdom of Sweden,

residing at Gottenborg, Sweden, have inbearings having electricinsulation.

As is known, the leakage field passing through the bearings of electricmachines frequently causes the generation of large currents which heatthe bearings. If the rotor of such machines is journaled in ballbearings or roller bearings, the said short circuit currents have topass the comparatively small contact surfaces between the balls orrollers and the rings of the bearings and cause on account of the greatcurrent density that the balls or rollers as well as the bearing ringsare easily burnt so that the whole bearing may easily be destroyed. Alsoin other cases it may happen that strong electric currents pass throughthe bearings, as for instance the bearings of electric railway ortramway cars, such currents preventing in many cases the use of ballbearings. I

The invention has for its object a special construction of the bearingby the aid of which the said inconveniences may be obviated andelectrically insulated ball or roller bearings be manufactured ascommercial units 1n the same manner as standard,

types of ball or roller bearings without 'causingtroubles or requiringspecial arrangements when being mounted.

, of two (or more) concentric rings between i which insulating materialis provided.

Several constructional formsof the invention are illustrated in theaccompanying drawings in which: v

Figures 1 and 2 show ball bearings provided .with an insulated outerring while Figs. 3 and 4; show ball bearings'provided with an insulatedinner ring.

Referringto Fig. 1,,the outer ring of the ball bearing'is composed oftwo concentric rings 1 and 2 between which is placed a layer 3 ofinsulating material preferably bonding said rings together. Thisinsulaprevent electric currents tion may consist of fiber, mica, eboniteor the like, or a plastic, hardening, insulating material may be usedwhich is poured or pressed in between the rings 1, 2.v The bearing shownin Fig.1 is a so called guide bearing, 2'. e. a bearing which isfastened rigidly or with a slight play in the casing 4. It will be seenthat one of the metal rings furnishes a track face for the balls,

the other beingprovided with a plain bear-' ing surface. For preventingelectric short circuiting of both rings 1, 2 of such a bearing, in case,owing to an axial movement of the bearing in the casing, they shouldcome into contact with one of the covering plates 5, 6 of the bearing,insulating plates 7 8 are placed at each side of the rings 1, 2. Theinner bearing ring 9 is of usual construction. As will be readilyunderstood, the electric insulation used in the outer ring will frompassing through the balls and from-destroying them or their track in therings. I

In the constructional form shown in Fig.

2 the surfaces of the rings 1, 2 which engage faces are provided withannular grooves, as

is indicated in the drawing, thereis used a plastic, hardening,insulating material which is pressed in between both rings 1, 2, whenproperly adjusted in position relatively to each other. The bearingshown in Fig. 2 is a so called wandering'bearing in which the inner ringis rigidly fastened to the shaft while the outer ring may move to acomparatively great extent in axial direction. Since in thisconstruction the outer ring cannot come into contact with the coveringplates 5, 6 of the casing, the insu-I lating plates at the sides of therings shown in Fig. 1 are omitted.

In the constructional form shown :in Fig. 3 the outer ring 10 isconstructed in the usual manner whilethe inner ring is composed oftwoconcentric rings 11, 12 with insulation 13 inserted between them.Insulating plates 7 8 insulate the end surfaces of the inner ring fromthe adjacent metal surfaces of the flange 14: of the shaft and of thefastening sleeve 15 in case the bearing, as is shown in the drawing, ismounted as a guide bearing.

The constructional form shown in Fig. 4: differs from that shown in Fig.3 only in the different construction of the insulation 13. Theinsulating plates 7, 8 are in this case omitted, because of the outerring 10 being rigidly fastened to the casing while the inner ring ismovable axially on the shaft 16 to a comparatively great extent so thatshort circuiting of the rings 11, 12 on account of contact with theflange 14 of the shaft or the sleeve 15 cannot take place.

Although the invention is shown in the drawing as applied to ballbearings having two series of balls and a sphericaltrack in the outerring, it will be readily understood that it is not limited to said kindof bearings but may be applied to all'kinds of ball or roller bearings.

Having thus described the invention what I claim is: 1. In bearings ofthe kind described, a track ring composed of a number of concentric,undivided rings, and an electric ininner and an outer track member, oneof such members being composed of two metallic rings, and electricinsulating material disposed between such rings.

3. In a self-contained bearing, the combination of an inner and an outertrack memher, one of said members being composed of a metallic ringhaving track faces for the rolling elements, a ring having a plainbearing surface, and electric insulating material disposed between saidrings and bondin the same together.

In testimony that I claim the foregoing as my invention, I have signedmy name in presence of two subscribing witnesses.

CARL EMIL WIESELGREEN.

Witnesses KARL RUNESKOG, ERIo SWANSTRESM.

